I was trying to push my new canoe as fast as I could Saturday. It accelerated steadily up to about 5.7 mph but when I really started paddling hard, it started to lose a little speed. Does that make sense?
Hull speed
The speed in knots of a displacement hull (your canoe) is equal to 1.34 X sq root of the waterline length. In your case this should be equal to 5.6 knots or 6.1 mph. To go faster you need to expend enough energy to plane the hull or get a longer boat for more waterline length. Whole books have been written on this subject.
Thanks. What that translates to for me
is paddle at a relaxing pace and enjoy the inherent speed, which is pretty good.
Correction
5.6 knots = 6.4 mph
off the wall i speculate
that your slightly less than all out stroke is smoother and the boat is moving in more of a straight line with less pitch and yaw than your full on technique. did i say technique?
Technique?
– Last Updated: Mar-08-04 7:13 PM EST –
I think Danny is right about your technique. Your efficiency probably goes south when you try too hard. All the stuff said about hull speed is true, but I don't think it applies in this case since you actually slowed down. At hull speed, one would expect that with increased effort it would get extremely difficult or impossible to go faster, but you wouldn't slow down.
There are more expert paddlers here than I and I hope they weigh-in here, but I'll guess you are making a stroke that is too long. If you put a lot of energy into portions of the stroke where you are "reaching", you won't put as large a proportion of your effort into straight-line propulsion. With your boat, I doubt you will notice much yaw since it tracks so hard. Also, misdirected paddle force can be downward, tending to lift the boat (when reaching forward) or up, tending to pull the boat down (when reaching back). I see the same thing when rowing. When I really want to sprint, a long stroke won't get me to as fast a speed as rapid, short strokes. In this case, reaching too far causes the oars to push water out and away from the boat when at the beginning of the stroke, and then toward the boat at the end. During the center of the stroke the force is straight back, which is the most efficient direction to push, so a large number of short strokes in that "center" zone create a higher top speed.
I recently read an article about using a bent-shaft paddle for speed and all-day efficiency, and the author suggested using incredibly short, rapid strokes, with the purpose being to apply effort only within that narrow zone of your reach where the power face of the paddle faces directly toward the rear.
Don't know if that helps, but that's what comes to mind.
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I just looked at the photos provided with your other post. FIRST, let me say, What a lovely boat! I've only seen one on the water one other time - the Voyager is sure an eye-catcher!
Second: After looking at your kayak paddle and its angle in the water during part of the stroke, I'd suggest you get yourself a bent-shaft single-blade and try it out. You might be surprised at how fast the thing will go. You'll have to sit-and-switch to make the best use of it though.
Once again, Gosh that boat looks like fun! I'm jealous.
Read better books!!!
Narrow hulled vessels like kayaks and canoes surpass hull speed all the time and do NOT have to plane to do so.
Stern Squat begins around S/L (Speed/Length ratio) 1.0. Displacement begins to increase.
“Hull Speed” is S/L 1.34. A wave lenght limit, not a speed limit. Faster canoes and kayaks can be sprinted above this fairly easily.
Dispalcement equalizes (to same as static amount and then begins to decrease) at S/L 2.2 and up. Olymians are at S/L 2.0 - 2.2 in K1 sprints! (Not sure how to arrive at this and if it varies with width as it’s not a wave function like hull speed - sailing folks should know as they operate in this intermediate range a lot).
Planing is somewhere above S/L 3 (don’thave number) - no one goes there under paddle power.
Technique
Yup, I get same thing in my kayak. Steady accelleration up to a certain point - then if I add more power I lose gound!
I back off a bit and focus on stroke technique and it goes back up. Keeping that feel, I can gradually add in a littel more to get a little more.
Hours on the water with attention to technique is the fix. Don’t expect top speeds now. Work on smooth reliable speeds over distance first. More will come.
Actual cause is possibly everything mentioned. Any part of the stroke or boat attitude can contribute.
For me it seems mostly to be from over powering the paddle. Makes it move more thought the water instead of staying planted. I lose more energy to moving/swirling water and less applied to moving the boat.
Did I mention: Technique?
Speed?
I don’t know a whole lot about paddling, but I know swimming. Similar problems occur with swimming. As you go faster, more effort is required to go faster. All kinds of ways to keep your body streamlined. In fact, proper form will move you faster than strength or conditioning in swimming. Here is the correlation though. One very critical aspect is what they call the catch. It is the beginning of your arm stroke. If you mess up the catch your stroke will not move you as far forward. Underwater filming shows that when you get the catch right your hand will actually be moving forward instead of backwards. Anyway, I noticed when we were out a few weeks ago that when I took a hurried stroke that I didn’t get that good “catch”. I could hear the air around the paddle. Air is no good for propulsion. Anyway, when you start trying to pull harder and faster, you sometimes lose form and that is the crucial ingredient for go fast folks…My 2 cents!
Get Spring Creek stabilizer setup, then
replace them with JATO packs.
Seriously, though, in addition to the other points, keep an eye on your bow and try not to bounce the boat too much. Also, getting the blade planted properly before the catch will reduce “check” which is caused by part of your mass going toward the stern before you have hold of the water. Checking the boat is that hesitation you see in competition rowing shells as they take the catch and all that body mass starts back toward the bow of the boat without the oars being locked in the water.
my common mistake…
is to take too long and deep a stroke. At the end of the stroke, the paddle pulls up on the water. This works as a brake and also pulls the canoe side-to-side.
Good advice everyone. I have a bent
shaft paddle but I just haven’t been able to wean myself from the kayak paddle. It just feels better to me and I can do a whole lot better sweep stroke.Now that spring is almost here, I will get a lot more practice.
I’ve Paddled My Voyager
Only a few times. When I did, I kept up with very fast sea kayaks. I would guess my speed a bit over 6 mph. This was with a SHORT (49") Meany bent-shaft paddle. The Voyager is EXTREMELY FAST…
I’m in Michigan, and I’m thinking of selling the Voyager. I have some mixed feelings, for sure.
Actually
The multiplier 1.34 is for true displacement hulls. As hull forms change the number changes slightly. Here is a better method for non-heavy displacement hull forms.
D/L Ratio (Displacement/length) note D must be in long tons (2240lbs)
D/L=(weight/2240)/(.01 x LWL)^3
S/L=8.26/(D/L)^0.311
Hullspeed= S/L*LWL^0.5
for weight–use total weight in the boat plus boat weight.
Voyager
How much ya want for it?
Unit verification and questions???
Just to check [units?]
D/L=(weight [in pounds?]/2240)/(.01 x LWL[in decimal feet?])^3
S/L=8.26/(D/L)^0.311
Hullspeed[knots?]= S/L*LWL^0.5
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and what the heck is “^”? My limited math skills don’t cover that symbol.
Also, if there is a a variability for S/L to calc Hull speed (I was told this number was 1.34 because it is a constant having to do with wave formation - not the hull, unlike other S/L related numbers) wouldn’t Hull speed be: (this new) S/L * (SQRT)LWL?
cool!
You guys are great…I’ve always wondering about the physics behind canoe speed. It’s apparently quite different than cars or airplanes.
So - can you tell me why some boats can be forced through and beyond their hull speeds more easily than others? I’ve always been curious and see the other post about Wildfire top speeds.
Thanks for the education!
Easy!
Hull speed is not top speed. It’s only the point at which the wavelength of the bow wave coincides with the LWL.
You can never pass your own bow wave as you make it as you go.
It get’s harder as you go faster becuse to get the boat moving faster you have to push the bow wave along faster (not beacuse you’re “paddling uphill” on the bow wave!), and all water you are displacing has to be pushed out of the way faster.
Much below hull speed the friction & dispalcement (form drag) offer the biggest resistance - and wavemaking is not much of a factor. As you get closer to hull speed (and beyond) dispalcemetn increases, and wave drag is increasingy a factor as speed increases.
This is why some shorter boats have SLIGHTLY lower drag numbers at low speeds (less form drag), why most kayaks are somewhat close in drag at common touring speeds (the curves all tend to intersect somewhere between 3-4 kts), and long boats are better at speeds nearer and over hull speeds (longer boats have longer bow wavelenths and don’t “hit the wall” until nearing or over their correspondingly higher hull speeds - depending on paddler power).
Simplified, and based on my somewhat limited understanding so I may have said something the wrong way somewhere, but that’s the basics.
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